The present invention pertains to a lighting control system, and more particularly, to such a system which includes apparatus designed to provide cue-level performance confirmation.
Automated and/or semiautomated lighting-control systems are becoming today more widely used in connection with controlling the illumination in a space, such as a stage. Such a system typically employs a computer which works in conjunction with master control apparatus, such as a typewriter-like keyboard, to allow for sequential storage of the different so-called lighting "cues" which are intended to be used during a performance.
More specifically, in the use of such a system, an operator of the system, under the supervision of a lighting director, adjusts the intensity levels of different specified lights during the setting up of a particular lighting cue. This is done, for example, through keyboard communication with the computer to indicate which lights are to be set at which levels. When the director is satisfied with the illumination level, and the nature of a particular cue, and so instructs the system operator, the latter instructs the computer to store in a memory data exactly reflecting the illuminated conditions of the different lights. This procedure is repeated for all of the different cues that are to be used during a performance, and the computer is instructed as to the appropriate sequence for the cues.
During an actual performance, the system operator, again under supervision, and through communication with the computer by way of the keyboard, "calls up" the different successive cues as required by his directions. These cues are "called forth" from the computer's memory, and the latter provides all of the appropriate control signals to turn on the appropriate lights at the appropriate intensity levels. Where fading in and out is required, this may be performed either manually or automatically.
Ideally, and during a performance, the different successive cues exactly repeat what was established for the cues at the time that they were intially set up and stored in computer memory. As a practical matter, however, it sometimes occurs that the actual intensity of a lighting cue during a performance is higher or lower than that expected, by virtue of a change in line voltage, or in some cases by the fact that one or more lamps are dead. Often, this situation is not detected by the people directing the performance, or at least not in time to make a correction.
A general object of the present invention is to provide a lighting-control system which obviates this difficulty in a practical and satisfactory manner.
More specifically, an object of the invention is to provide a system which affords the capability, during setting up of a lighting cue, of monitoring the light-intensity level produced by the cue, with this information stored in computer memory and related to the particular cue.
A further object of the invention is to provide a system of the type so far generally outlined in which, during an actual performance, the data stored in computer memory reflecting the expected intensity levels of the different cues are compared, on a continuous basis, with the actual intensity levels produced by the real-time cues as they are called into being. This comparison is used to generate a signal which, at the very least, will simply tell a system operator whether the light intensity is too great or too small, so that he can make an instantaneous correction. A somewhat more sophisticated system utilizes this kind of signal to effect, through computer control, an automatic adjustment in cue intensity level.
Thus, a preferred embodiment of the invention comprises a stored-cue lighting-control system for controlling the illumination of a selected space, such as a stage. A photodetector is provided in the system for following the level of illumination in at least a selected portion of the space. During storing of cue data associated with a particular lighting cue, related data, regarding the level of illumination intended to be produced by the cue, is also stored. During functioning of the system to place different successive cues in the space, the stored illumination data is compared with current real-time data reflecting the actual illumination level then being produced in the space. An indicator in the system signals any difference noted as a result of this comparison. In a simple form of the invention, this signal tells an operator whether intensity level is too high or too low, and allows for immediate correction. In a more sophisticated version, this signal effects automatic computer correction of the condition.